Apparatus for the electrostatic separation of material particles



Aug. 14, 1945.

E. L. WIEGAND 2,382,122

APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES Filed July 21, 1941 12 Sheets-Sheet 1 .llhilul ATTO'RN EY5 Aug. 14, 1945. V .E. L; WIEGAND 2,382,122 APPARATUS FOR THE ELECTROSTATIC'TSEPARATION OF MATERIALXPARTICLJE? 1 .Filed July 21, 1941 '12Sheets-Sheet 2 EbW/N L. VV/EGAVND INVENTOR M d d W AT oRNEYs Aug. 14, 1945.; 51.; WIE GAND 2 APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES Filed'July 21, 1941 12 Sheets-Shee't 3 Eoww LJW/EGH/VD M INVENTQR 1 1 B z a: v i ATTORNEYS I Aug. 14, 1945. E. L. WIEGAND 2,382,122

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Aug. 14, 1945. E. L WIEGAND 2,332,122

APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES I Filed July 21, 1941 12 Sheets-Sheet 5 INVENTOR AT TO R N EY$ Au 14, 1945. E. L. WIEGAND APPARATUS FOR THE ELECTROTATIC SEPARATION OF MATERIAL PARTICL Filed July 21, 1941 12 Sheets-Sheet s [0 W/N L. W/Ean/vp W INVENTOR' ATTORNEYS E. L. WIEGAND APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PA RTICLES Filed July 21, 1941 12 Sheets-Sheet 7 [Ow/N L. VWEGH/VD .91?

INVENTOR J14 712; /42 W ATTORNEYS:

Aug. 14, 1945. E. L. WIEGAND ,1 2; APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES I Filed July 21, 1941 12 Sheets-Sheet 8 NVENTOR BY WWW ATTORNEY5 RTICLES Aug. 14, 1945. E. 1.. WIEGAND APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PA Filed July 21, 1941 12 SheetsSheet 9 dm% 0 Mfl WWW 3; J W \ffi t J j M I M m. w y @i. 1M Z T w W: 1 a 7V in A fi l "a; M w M Q. M a ,w a: i K m 5 gwfw w 4 1 @flw 0 v 1 H fl fi w 14 m fi g F E 0 W/N L; VV/EGQ/VD INVENTOR MW ATTORNEYS Aug. '14, 1945. E. 1.. WIEGAND r 2,382,122

APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES Filed July 21, 1941 12 Sheets-Sheet 1O F/QQZ [ow/N A. VV/EGHND INVENTOR 2 W BY MTTORNEYS Aug. 14, 1945. E. 1.. WIEGAND APPARATUS FOR THE ELECTROSTATIC SEPARATION-OF MATERIAL PARTICLES Filed July 21, 1941 12 Sheets-Sheet 11 INVENTOR BYMMW AT TORN EYS Aug. 14, 1945. E. 1.. WIEGAND 2,382,122

APPARATUS FOR THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES Filed July 21, 1941 12 Sheets-Sheet 12 [ow/N L. WxEcm/vo IN V E NTOR rimw w ATTORNEYS Patented Aug. 14, 1945 APPARATUS FOR' THE ELECTROSTATIC SEPARATION OF MATERIAL PARTICLES Edwin L. wieganiLPittsburgh, Pa., assignor to Orefraction Incorporated, Pittsburgh, Pa., a corporation of Pennsylvania Application July 21, 1941, Serial No. 403,267

16 Claims.

My invention relates to electrostatic separation of material particles, and the principal object of my invention is to provide new and improved apparatus for electrostatically separating material particles. 7

In the drawings accompanying this specification, and forming a part of this application, I have shown, for purposes of illustration, forms which my invention may assume, and in these drawings:

Figure 1 is an end elevation of apparatus embodying my invention and certain auxiliary apparatus fragmentarily shown,

Figure 2 is a rear elevation of the apparatus shown in Figure 1,

Figure 3 is a vertical sectional fragmentary enlarged view of an upper portion of the apparatus shown in Figure 1,

Figure 4 is a fragmentary partly sectional view taken on the line 4-4 of Figure 3, looking in the direction of the arrows,

Figure 5 is a fragmentary sectional view taken on the line 55 of Figure 3, looking in the direction of the arrows,

Figure 6 is a vertical sectional fragmentary enlarged view of a lower portion of the apparatus shown in Figure -1, v

Figure '7 is a section taken on the line 1-1 of Figure 6,

Figure 8- is a vertical sectional fragmentary view, on an enlarged scale, of detail parts including a feed hopper and a feed gate or valve, the section being taken on the line 8-8 of Figure 11,

Figure 9 is a fragmentary perspective view, partly in section, showing certain parts of the feed valve, disassembled.

Figure 10 is a fragmentary perspective view, partly in. section, showing certain other parts of the feedvalve,

Figure 11 is a fragmentary sectional view taken on the line ll-ll of Figure 8, Figure 11 beingv on a smaller scale,

Figure 12 is a fragmentary sectional enlarged view taken on the line I2-I2 of Figure 11,

Figure 13 is a fragmentary sectional view of a detail, 1

Figure 14 is a fragmentary view of a portion of Figure 3, enlarged,

Figure 15 is a fragmentary elevational view of certain details,

Figure 16 is a fragmentary sectional view, on a reggiced scale, taken onthe line l8--I8 of Figure 1 view taken on the line -|1 of Figure 14, and showing an intermediate valve or gate, v

Figure 18 is a sectional view taken on the line l8l8 of Figure 17,

Figure 19 is a fragmentary perspective enlarged view, partly in section, including parts of the intermediate valve or gatefshown in Figure 1'7,

Figure 20 is a fragmentary and elevational view showing more or less diagrammatically the feed hopper of the apparatus of Figure 1, along with means for feeding material to the-hopper,

Figure 21 is a fragmentary plan view showing feed conduits for the feed hopper and one way of feeding material to the hopper,

Figure 22 ,is an end elevational diagrammatic view of the flow of material to the feed hopper Figure 23, 24, 25, and. 26 are flow diagrams showing various ways in which the material may flow through the separating apparatus when the feed hopper is fed as shown in Figures 21 and 22.

Figure 27 is a view corresponding to Figure 21 but showing a different way of feeding material to the feed hopper of the separating apparatus,

Figures 28 and 29 are flow diagrams showing several ways in which the material may flow through the separating apparatus when the feed hopper is fed as shown in Figure 27,

Figure 30 is a view corresponding to Figure 2 but showing a different way of feeding material to the feed hopper of the separating apparatus,

and

Figures 31 and 32 are flow diagrams showing several ways in which the material may flow through the separating apparatus when the feed hopper is fed as shown in Figure 30.

Referring to the drawings and to the apparatus as a whole, the separating apparatus herein shown is adapted for the purpose of passing the particles to be treated through at least one electrostatic treating zone, on or more times, or

successively through a plurality of electrostatic Y treating zones one or more times, whereby the particles are separated into two fractions one 'being usually used to designate the desired or Y most desired fraction and the term tails the least desired or perhaps .undesired fraction, but in' 5 many instances each fraction is useful for some gure 17 1S a fragmentary sectional broken purpose. Moreover, it will be apparent that if 1 tlble particles will be termed the fraction comprising the most susceptible ar ticles happens to'be most desired this fraction may be called the heads 'whereas if the fraction comprising the least susceptible or non-susceptible particles happens to be the most desired mam - may to the feed hopper it through conthis fraction ay be called the heads. However-g merely for the sake of brevity and convenience in describing the disclosed apparatus that fracbeing designated by "the numeral lv with letter sufllxe's to correspond to the treating zones, whereas the particles removed from the zones 1!,

D, F, and H are adapted to be segregated in tails hoppers, at the "rear" of the apparatus, likewise designated with the name 1 III and letter sumxes. Chutes it may be provi per, so that the-lowermost front tails hopper I00 receives not only the tails from the treating zone 'duitmeans O1 in various ways as will more fully appear. The elevator 64 may receive material to be treated through conduit means ts from a bin ll fragmentarily indicated in Figure 1.

' An elevator "may also be provided, to the spout ll of which may beconnected a conduit 12 to feed material tozthe hopper 63 in ways to be described. The elevator is provided with inlet spud: 13, H, "1! to a selected one of which 1 material may be fed under certain circumstances as will appear.

A reversible electric motor 18 suitably mounted wcrew 11 (Figures 3 and, 4) which may be '11!- llledBin the feed hopper a: for uitably distribu ng the material in the bottom of the hopg per. The reed screw 11 may be driven by a sheave ed leading from each front tailshopper to the next lower hop G but thetailsirom all or the preceding hoppers in the front series. In like manner chutes lil may be provided so thatvilielowermost rear tails hopper h receives not only the tails from the treating zone H but from all of the preceding hoppers in the rear series.

Interposed between thezone A and the zone B is an intermediate hopper 52a adapted to receive all materialfrom the zone A not discharged into the tails hopper We, the material from the intermediate hopper 52:: being adapted to be fed into the zone B. As far as the zone A is con cerned the material in the intermediate hop-- per may be termed heads, or, in theillustrated apparatus, intermediate heads. In like manner intermediate hoppers are interposed between each successive pair of the other treating zones, these "intermediate hoppers being designated by the numeral 52 plus a letter suflix corresponding to the zone from which the intermediate hopper receives heads," and all of the intermediate hoppers may, be' of identical construction.

The heads from the lowermost treating zone, H, are discharged into a final or main heads hopper 53.

The parts of the separating apparatus may be carried on a supporting irame I4 comprising four vertical angle bar standards, one pair of standards 55, 56 being atone end of the apparatus and another pair of standards 51, I. being at the other end. The standards 5!, BI, and I1, I, and 55, 51, and 56, II are respectively interconnected by cross braces ll, 80, 8|, .2.

Suitably mounted onthe upper end of the supporting frame 54 is a feed hopper 83 adapted to feed material to be treated to .the first treating zone A. In the embodiment shown material may be fed to thefeed hopper 03 from an elevator 84 diagrammatically indicated in?) res 1 and 20, and in this particular embodim' here is shown interposed between the spout 8gp! the elevator 64 (see Figure 20) and the feed' hopper 63 an auxiliaryhopper 68 from whiclr' ihaterlal II on the shaft of the screw 11 by means of a belt 18 cooperating with a sheave 80 on a speed reducing. means 8| driven by the motor 16.

The tails hoppers 50g and lllh also may be provided with feed screws 82, II respectively (Figure 6).- The feed screws 82, li'may be driven by sheaves M, II on the respective shafts of the feed screws 82, 83, by means of belts 86, 81 cooperating with a sheave 88 on a speed reducing means I! driven by a reversible electric motor 80 suitably mounted on the frame 54 as by a support platform 360.

Referring now more particularly to Figures 3 and '4, the feed hopper 83 is here shown as of horizontally elongated form. The hopper 63 is open at the top and has vertical side walls 91, 98

Material is adapted to be discharged through a series of holes ID! in the bottom of the feed hopper l3, thence through feed valve means H0, as will more fully be described. The material 7 discharged through the valve means H0 is received on the bottom of a chute llla forming part of the treating zone A. The chute Illa comprises a. metallic bottom plate 2a here also serving as an electrode. The plate ll2a extends downwardly at an angle to the horizontal greater than the angle of repose of the material particles. The longitudinal ends or the plate 2a are bent downwardly so as to form flanges 3a, Illa (see also Figure 17) to which are respectively fastened, as by bolts and nuts Ilia, plates llIa, Illa of Micarta" or other suitable insulating material, these plates forming the outer 9,382,122 I side walls of the chute Illa. "The side walls Illa, Illa are here shown as spaced from and slightly overlapping the end walls 99, Ill of the feed hopper ll. Cemented or otherwise suitably fastened to inside surfaces of the side walls Illa, Illa are plates Illa, Illa of glass or other'suitable material which serve as a lining for the side walls. The plates Illa, Illa need not cover the entire length of the side walls Illa, Illa.

Disposed above the plate Illa is a plate electrode Illa supported by a plurality of insulators Illa as will more fully appear. Ordinarily, but not necessarily, the electrode Illa will be positively charged and the plate Illa grounded by reason of its connection with the frame 54, so that, for the sake of brevity, the electrode Illa and the plate Illa may be hereinafter referred to as positive electrode and negative electrode respectively.

The upper end of the chute Illa is supported by a plurality of angle brackets Illa (see also Figure 8) which may be fastened by bolts and nuts Illa to the plate Illa and by U-bolt clamps Illa to one of the cross braces 6|.

The tails hopper 50a has a vertical wall Illa most of the length of which is recessed or cut away from its top margin Ilia down to a margin Illa. This margin Illa is approximately common with the upper margin of a bottom wall Illa of the tails hopper 50a. The wall Illa, in this instance, extends upwardly at an angle to the horizontal about the same as the plate Illa but the plane of the bottom wall Illa is here shown slightly below the plane of the plate Illa. The tails hopper 50a has another vertical wall Illa extending from the top of the hopper downwardly and merging with a rounded bottom wall portion Illa provided with a plurality of apertures Illa through which tails may be discharged into the associated chute 5I and thence to the next lower tails hopper 5Ilc. tails hopper 50a has vertical end walls Illa, Illa, The uppermost margins of the walls of the tails hopper have angle bars ll5a suitably fastened thereto and comprise part of a frame to make the hopper more rigid and for supporting the hopper. For the latter purpose the frame has ears Illa fastened by screwv bolts Illa to the angle bar standards 58, 56.-

The chute 5I is here shown as hung onto the tails hopper 50a by pins or screws llIl extending through ears lll into or through the respective end walls Illa, Illa of the tails hopper, the

ears lll being upward extensions of the end,

walls lll of the chute. The upper ends 312 of the side walls 314 of the chute 5I are flared outwardly and may abut the outside of the bottom wall Illa of the tails hopper. The end walls 313 of the chutes 5| are here shown as slanting inwardly as seen in Figure 2. The chutes 5| are herein shown as all identically constructed.

The length of the margin Illa is somewhat greater than the width of the chute Illa from side wall Illa to side wall Illa and these side walls (but not the plate Illa) extend into the tails hopper. Lower margins of the side walls Illa, Illa may rest on the margin Illa or its equivalent as will more fully appear. 7

Extending from between the upper margin of the positive electrode Illa upwardly approximately to the feed hopper 63 is an insulating plate Illa the ends of which extend through slots Illa in the side walls Illa, Illa. Screws lllla, bearing against washers Illa larger than The the width of the 516m. Illa, are screwed into ends of the plate I lla'to limit itslongitudi'nal movement. The plate Illa is here shown as provided with transverse slots Illa to accom modate the glass plate Illa. The plate Illa serves as a baille to prevent particles of material which may move from the negative electrode Illa upwardly in the space under the baffle from getting above the positive electrode Illa.

The negative electrode Illa has a lowermost margin Illa which is spaced from the margin Illa, whereby particles falling through this space may be received in the intermediate receptacle or hopper 52a. Adjacent the margin Illa may be provided adjustable dividing means Illa here shown as comprising an elongated insulating plate, to be further described.

Material from the intermediate hopper 52a may be discharged to the second electrostatic treating zone B which includes a chute ll lb comprising a metallic plate electrode Illb, and side walls Illb, lllb, and glass liners Illb, Illb, similar to the chute Illa. As will more fully appear, the feeding of material from the intermediate hopper 52a onto the plate Illb is controllable by valve means I451). The chute Illb is related to the tails hopper 50b and to the second intermediate hopper 5lb in the same way as is the chute Illa of the first treatingzone, A, to the tails hopper 50a and 'the intermediate hopper 52a. The upper end of the plate Illb may be supported by brackets 8b from a cross brace ll.

The zone B-includes a positive electrode Illb similar in all respects to the electrode Illa. A baille Illb, similar in construction and purpose to the baflle Illa, is provided extending from between the upper margin ofthe electrode Illb upwardly approximately to the nearest side of the intermediate hopper l'lla.

The side walls Illa, Illa have apertures llla, here shown as oblong rectangular, cut therein,

thus exposing the glass liners Illa, Illa at these v places, in order that, if desired, the action taking course that, as shown, the chutes of successive zones are directed in successively opposite directions.

The zone G (see Figure 6) is similar to the zone B except that the tails hopper 50g associated with the zone G is provided with the feed screw ll. The zone H is similar to the zone G but differs from the zone G in that instead of an intermediate hopper, such as 52g, below the space between the lower discharge margin Illh of the negative electrode IIlh and the entrance margin I50 of the tails hopper 50h, there is provided the final heads hopper 53 the construction of which, with certain exceptions, is like that of the tails hopper 509. The upper margins of the walls of the heads hopper 53 may be provided with a frame similar to the frame Illa and this frame may be supported from the support means lll (Figure 1) or in any other suitable way. The lower end of the negative electrode Illh valilebody is adapted t? I 61, so that, iir this instan particle receiving recess.

may be suitably supported by an angle bar1I41 extending across the inside of the heads hopper 63 the ends of the angle bar being supported in any suitable way. by the end walls I48, I 49 of the heads hopper. Here shown as disposed between the entrance margin I50 of the tails hopper 5011. and the upwardly projecting margin II of the bottom wall I52 of the heads hopper 58 is a dividing means comprising an insulating plate I53, in this instance fastened by bolts and nuts I54 to a metal plate I55 having a bent-over upper. margin I56 hung over the margin I 5I. If

1g desired the insulating plate I 58 may also be made vertically adjustable in any suitable way so that the amount the ripper margin of the plate. ex-

tendslabove the plane of the negative electrode II2h may be adjusted.

The tails hopper 509' is provided at its bottom with cylindrical extensions I 51c: (see Figure 7) at both ends, the feed screw 82 extending into these extensions, the ends of the shaft of the feed screw 82 being supported by bearings I58g supported by the ends of the cylindrical extensions. The extensions I519 are provided near their ends with discharge spouts I60g, directed downwardly to; the left as viewed in Figure '6 and outwardly as viewed in Figure '1. The spouts I600 may discharge the material into receptacles inot shown) or may have conduits (not shown) connectedtheretii to lead the discharged material to any: desired place. The construction of ,the tails hopper 50h isthe same as the tails hopperv 509 but litris arranged reversely to the tails hoppfir 50g asfvident from Figures 6 and 7.

The heads hopper 53-is constructed'the same as the tails hopper 509 except that in addition to discharge spouts I81, similar to the spouts I809. at the ends of cylindrical extensions I62, it has a pair of discharge spouts I63, in this instancecommunicating with the bottom of the hopper at its respective ends near the end walls I48, I49, the-spouts I63 beingdirected at an angle downwardly in a direction to the right as viewed in Figure 6 and'inwar'dly as viewed in Figure 7. Either selected one of the spouts I6I is adapted to discharge into a receptacle and'either selected one of the spouts I63 is under certain conditions adapted to discharge into a conduitinot shown), and selected {ones of the spouts in general may closed byiflosure-caps as will appear. Referring nown rnore particularly to Figures 8 through 12. A'tj'the junction of the walls I04, I05 01 the feed hopper 63 araprovided the small holes I09 forming a series-DQ110165: (see .also Figure 11) extending substantially the full length of the hoppergf'through which imaterial may discharge, this discharge being controllable by the feed valve means-1.1. I0. .fl?'he;f ejed"valve means-J10 comprises a reltivelyfitationary plate I55 fastened by bolts and nuts. I66 to the wall l05 The plate I65 has a beveled surface I61""providing a valve seat for, ih this instance two valve bodies I68,. I6-9. A bodies I6 8 ,..I69 may be scribed as made -;of rectangular section rod 'st'ock one comer being beveled oiT forming a bevell face I10 and the opposit corner being rounded'i flf to form a round face-"ELM. Th'eedge I12 ,oia 'surface I64 of each gage the bevel face when the valve means 61 form a V-sh'apjed The inner end of the valvebody I68 is provided-with a cylindrical'pinis closed, the surfaces 6 j plate II2a (see Figure 11).

coextensive portion I14.

as to form the pintle and leave intact a'portion I14 coextensive with the-pintle, the end faces I15, I16 of the pintle and portion I14 being in such instance in the same plane. The pintle I18 is adapted to be received in one end of a cylindrical hole I11 provided by a bearing member I18 carried by a plate I19 fastened by bolts and nuts I to the wall I04. When the pintle I13 of the valve body I68 is inserted in the left hand end of the bearing member I18 the outer and inner walls of the bearing member fit in the arcuate slot I8I between the pintle I13 and the valve body I69 '(see Figure 10) isformed analogously to that of the inner end of the valve body I68 so that when the pintle I13 of the valve body I69 is inserted in the right hand end of the hearing member I18 the respective inner end surfaces I16, I16, or at least the surfaces I16, of the valve bodies are in contact. Consequently, when both valve bodies I68, I69 are in the closed position shown in Figure 8 in which the edges I12 of the valve bodies are in contact with the surface I61, these edges will define a continuous line of contact there being no interruption in spite of the presence of the bearing member I18.

The outer ends ofthe valve bodies I68, I69 are provided with pivot pins I82 respectively cooperating with bearing holes in end bearing plates I83 (see Figures 9, 10, and 11) which are disposed against the stationary valve plate I85 to which the end bearing plates may be fastened as by screw bolts I84 (see Figure 12). The ends of the plate I65 being flush with the end walls 99, I00 of the feed hopper, the plates I83 also bear against these walls respectively, and as here shown the plates I83 extend downwardly to the The end bearing plate I83 for the valve body I68 thus also serves to close the outer end of the space'between the surface I64 of the valve body I68 and the surface I61 of the valve plate I65, so that no leakage of material can occur from the end of that space. In like manner the end bearing plate I83 for the valve body I69 serves to close the outer end of the space between the surface I64 of the valve body I69 and the surface I61 of the valve plate I85.

There being two valve bodies I68, I68 the operating means therefor is in two independently operable parts I85, I86 which are substantially identical so that only one need be described. The valve body I69 has rigidly fastened thereto in any suitable way an arm I81 having an offset portion I88 merely for the purpose'of clearing other parts of the apparatus. The outer end of the arm I81 is pivotally connected by a stud I89 (see also Figure 2 to a. bushing I90. The bushing I90 has a hole I 9| through which freely passes a threaded rod I92. Engageable with the lower endof the bushing I90 is a threaded knurled nut I93, and engageable with the upper end of the bushing is a threaded nut I94 provided with a hand wheel I95. is not threaded and is disposed with a sliding fit through a bushing I96 (see Figures 1 and 2) suitably fastened to a support I91 fastened in any, suitable way to the frame '54. The bushing I96 has a; threaded transverse hole to accommodate a set screw I98 for holding the rod I92 in adjusted position. The lower end of the rod I92 is provided with an indicator I99 which may be adjustably fastened to the rod I92. The indicator I99 cooperates with a chart 200 the The inner end of the- The lower end of the rod I92 ordinates of which indicate predetermined posi-.v

tions or the valve body I66 from closed to fully open, and the abscissae or which indicate flow of -material through the valve in, for example,

pounds per hour. In adjusting the valve body I66 to a new position, the set screw I68 is loosened and the rod I92 may be moved to the desired position by an operating knob 26I fastened to the rod. The relationship between the valve body I89 and the indicator I98 and chart 266 may be adjusted by the nut I93 and hand wheel I95, so as, for example, to bring the indicator I-99 to zero abscissa when the valve body I69 is in closed position.

Since the rods I92 of the respective means I85, I86 for operating the valve bodies I68, I69 are offset from the central plane of the apparatus, as may be seen in Figure 2, the arm I81 of the means I85 is bent to the left and the arm I81 of the means I86 is bent to the right (see also Figure 11).

Means is provided to urge the valve bodies I68, I69 axially toward each other, so that the end faces I16 of the valve bodies will be held in engagement, this means being here shown'as a tension spring 262 the ends of which engage projections 263 on the arms I81 respectively.

The arms I81 extend to their respective valve bodies I68, I69 through a recess 264 Provided in the upper part of the plate II2a, which accom-' modates the arms in moving from the full line position shown in Figure 8 to the dotted line position there shown in which the feed valve means is fully open, the surface I64 being then substantially parallel to the surface I61, In this position the surface I64 and a plane surface 265 provided on the bearing member I18 definea common plane.

The plate II2a is here shown as having an upper end portion 266 bent upwardly forming a flange bearing against the underside of the plate The bearings I61, I68 for the shaft I66 of the feed screw,1.1 comprise a packing gland 261 and packing 268, as seen in Figure 12; and fastened by set screws 269 to each end of the shaft I66 is a thrust collar 2I6 which may carry a cylindrical guard 2II disposed about packing 2I2 between the collar and bearing member. Grease cups 2 I3 may be provided.

Referring now to Figure 14,- this shows, among other things, a section of the positive electrode I 23a and one of its supporting insulators I 24a. However, the construction of the positive electrodes I23 (a through h) and the supporting and adjusting means therefor is the same and therefore a description of these parts for the zone A will serve for all.

The positive electrode I28a is in the present embodiment an elongated rectangular metallic plate (see also Figure 4) extending almost the entire width of the chute II Ia leaving only suitable clearance between the ends of the electrode static field, the particles are under the influence of the field a considerable distance and a considerable time before they reach the vicinity of the discharge edge I430. Furthermore, it will be noted that the electrostatic field between the electrodes extends at a downward angle with respect to the horizontal and, more particularly,

The electrode I23a, as here shown, extends not only over the negative electrode I I2a but also beyond the discharge edge I43a, and also over the gap between the discharge edge I43a of the negative electrode and the entrance edge I21a of the tails hopper. segregating action as will appear,

The electrode I23a is supported by any suitable number of insulators I24a, in this instance three,-

- spaced longitudinally of the electrode. The inplate and the glass plates I 2Ia, [2211. The elec- .Margins 22I through which the screws 2I9 extend are flared sulators I24a may be of hollow conical form fastened by a plurality of circumferentially spaced screws 2 disposed through an annular metal cup H5 and through a base flange 2I6 of the insulator to an elongated insulating plate 2 I 1 (see also Figure 4). The electrode I23d is here shown as fastened to the plate 2I1 in slightly spaced relation therewith by insulating buttons 2I8 and screws 2I9 extending through the electrode I23a into threaded recesses in the buttons. The buttons 2I8 have lateral recesses 226 in which the margins of the insulating plate 2I1 fit. of holes in the electrode I23a to accommodate the heads of the screws so that the tops of the heads are flush with the under side of the electrode.

The insulator I24a is supported by a metal rod 222 having a collar 223 and a reduced extension 224 disposed through a hole 225 in the top of the insulator, the end of the extension being threaded and cooperating with a nut 226, whereby the rod is fastened to the insulator. Disposed and held between the collar 223 and the top of the insulator I24a is an insulating guard 221.

The rod 222 is slidable freely through a hole 228 passing transversely through a hollow shaft 229, and the rod also extends slidably through a hole 236 in a boss 23I welded to the shaft 229. The rod 222 has threads 232 along a desired part of its length and this threaded part cooperates with a threaded hand wheel 233, by rotation of which the rod may be adjusted generally upwardly or downwardly, The distance the positive electrode I23a is from the negative electrode II2q may be gaged by the amount the end of the rod 222 extends beyond the hub of the hand wheel 233, or if desired, the rod may be provided in bearings 234 forming parts of support brackets 235. The details of one of these brackets 235 may be best seen in Figures 14 and 4. The bracket 235 there seen is fastened by bolts and nuts 236 to the angle bar standard 58, lugs 231 being provided-on the bracket,-the lugs engaging a, margin of the standard. A set screw 238 threaded into This-improves the separating and a boss on the bearing member 234 is adapted to engage the shaft 226 to hold it in adiusted position. Collars 299 are provided, pinned or otherwise fastened to the ends of the collar 229 to limit shaft 229, and graduations are provided on the arcuate surface, a pointer 2 on an arm 242 being adapted to cooperate with the graduations. A reduced end of the arm 242 extends through the shaft 229 and a nut 243 is threaded on the reduced end and holds the arm fastened to the shaft.

It will be evident that by loosenin the set screws 238 and moving the arm 242 the shaft 229 may be rotated in the bearings 234, whereby the positive electrode I23a may be adjusted so that the plane defined thereby may be either parallel to the negative electrode 241' or make some other desired angle with respect thereto.

The londitudinal margins of the plate forming the electrode I23a may be edged with rubber 244 or other suitable insulating material. The lower longitudinal margin of the electrode I-23a may have fastened thereto, as by screws 245 an elongated insulating baflle plate 245. The positive electrode l23a may be connected to a source of high electric potential (not shown) by terminal means 241a. The terminal means 241a. comprises a metallic support 248 for a pair of jacks or sockets 249, 258-(Figures 4 and 13) for receiving plug contacts provided on the ends of insulated conductors 25I, 252. The jack support 248 has a flange 253 held, as by screws 254 or the like,v to the insulating plate 2; and held between the flange 253 and the plate 2l1 is a resilient contact member 255 having a portion 255 engaging the upper surface or the positive electrode I23a.

The conductor 252 is a jumper of general U- shape having a plug on one end. inserted in the jack 256 of the terminal means 241:): and a plug on the other end. in a jack on the terminal means 241!) of the next lower positive electrode I23-b (see Figure 1). In like manner, as shown in Figure 1, there is a Jumper conductor 252 connecting the terminal means of each of the other positive electrodes respectively to the next lower positive electrode. The conductor 25I leads to the source the inside of the conduit serving to carry conductors (not shown) for supplying the motors I6, 96, 96.

Referring again more particularly to Figure 14,

. the intermediate hopper 52a has a vertical wall 256 the upper margin 259 of which is here shown as bent over and as hanging on the bent-over margin 26!! forming the entrance margin I21a of the tails hopper 50a. The intermediate hopper 520 has another vertical wall 2" an upper portion 262 of which is here shown as bent to the horizontal and as fastened'by bolts and nuts 263 to a lower portion 264 of the negative electrode plate I I 2a also bent to the horizontal. The

intermediate hopper 62:: has bottom walls 2", 266 one of which, 266, extends at a somewhat steeper angle downwardly than the negative electrode II2b of the zone B and'the other of which, 265, extends at an angle to the wall 266. The

walls 265, 266 merge in an arcuate portion 261 ire-- which are provided a series of apertures 266 (see also Figure 5), in this instance of oblong rectangular shape. The intermediate hopper 52a is as long as the width of the negative electrode H222 and has vertical end walls 269, 210 overlapped by portions 21Ib of the side walls II5b,

I I1b, respectively, of the chute of the zone B,

, these side walls being reduced in thickness where they overlap as shown in Figures 5 and 17 for example. As may be seen in Figure 17, the. side walls 61:, I I1a (as well as the similar side walls of the chutes of all of the treating zones) have their lower marginal portions 213a of reduced thickness thereby forming shoulders 214a which engage the top of the electrode I I2a. Since all of the negative electrodes are of the same width, lower ends of the portions 2 13a also overlap and are in engagement respectively with the end walls 269, 2180f the intermediate hopper 52a. The walls 269, 210 have upper corner portions cut away leaving margins 285 in the plane of the negative electrode II2a, so that the margins seat against the shoulders 214a of the side walls I I6a, II1a respectively. The portions 213a terminate in transverse margins 215 near the dividing means I44a, those portions of the side walls ll6a, II1a which extend downwardly from the margins 215 into the tails hopper 56a having lower margins 216 which rest on the upper edge of the bent-over part 259.

Fastened by bolts and nuts 211 to the under side of. the bottom wall portion 266 or the intermediate hopper 52a is a plate 218 constituting an auxiliary chute for receiving material discharged through-the apertures 258 in the bottom of the intermediate hopper. The chute plate 218 is here shown as having a beveled surface 219 which if desired may rest on the upper surface of the negative plate II2b. Discharge of material from the chute plate 218 onto the negative electrode 212 is controlled by the automatic valve means Ib as will fully appear.

Considering now the dividing means or plate I44a'shown most fully in Figures 5 and 14 through- I6, this plate is so mounted that it may be adjusted up and down, in contact with the inner surface of the wall 258 of the intermediate hopper 52a, so that the upper margin 2860f the plate may be adjusted with respect to the plane defined by the negative electrode 2:1. The upper marginal portion of the plate l44a is here shown as having a bevel surface28l slanting downwardly from the margin 286 towards the tails hopper bottom l28a, the margin 280 being thus of knife edge character. The bottom margin of the plate I44a may be beveled to accommodate the wall 266 when the plate I44a is adjusted to its lowermost position. The body of the plate I44a extends the full length of the inside of the intermediate hopper 52a except for a desired clearance for free movement (see Figures 5 and 15). The plate l44a has a pair of ears 282 (Figures 15 and 16) at its ends, these cars extending through slots 283 in 8,'98i3,1-88 I Y face of the gate 991 and the upper margins 3|! Fastened by bolts and nuts 291 tothe ears are U-clampe. 299 to each of whichis welded or otherwise fastened a downwardly extending rod 299. The rods 299 are provided with threads 299 at their lower ends and pass freely through transverse apertures through the arms 2" of clevlses 292 having threaded shanks fastened by nuts 293 to the flanges ll3b, Illb ofthe negative electrode 2b. Disposed between the arms 29l of each clevis and cooperating with the threads 299 on the rods 299 are threaded knurled wheels 299 by rotation of which the rods and hence the plate to may be raised or lowered. Pointers 295 carried by the ears 292 and cooperating with graduated plates 299 respectively are provided to indicate the position of the uppermargin 299 of the plate Hla. While the dividing means Illa has been described with special reference to the zone A it will be understood that all of the dividing means I (a through c) are of the same construction. The automatic valve means 9b is shown most of the knife edges 391 are in .the medianor general plane ofthe gate 291.

The gate 991 is biased toward closed position by weights 9 disposed at the outside of the chute walls 9b, 1!: respectively, the weights being adjustably held on depending rods 9 by set screws III, the rods being suitably fastened transversely to members 3l9 having holes 3I1 adapted respectively to receive the outer ends of horizontal rods 3" which extend inwardlythrough apertures 3l9 (see also Figure 15) in the side walls Il9b, I l1b, the other ends of the rods being inserted in transverse holes 329 in the respective arms 392 and are held in theseholes by set screws 92l. For the sake of clearness one of the rods 3" and the weight 3l3 supported thereby are broken away in Figure 17.

The apertures 3l9 are suitably shaped to accommodate the rods 3" when the gate 291 swings v away from the stops 299. The screws 399 also i extend through the aperturesl i 9 and the nuts 3 l 9 fully in Figures 14, 1'7, 18, and 19, and as a matter of convenience this valve means, 5b, wilibe described, but it will be understood that all of the automatic valve means I45 (b through g) are of the same construction. The valve means 9b comprises a swingable plate or gate 291 the lower portion of which is coextensive with the auxiliary chute plate 219. When the valve means is in closed position, as shown in the drawings, the gate 291 is approximately at right angles to the chute plate 219 and the upstream surface of the gate is in engagement with a pair of stop pins 299 suitably fastened to and projecting upwardly from the auxiliary chute plate. In the closed position the lower beveled margin 299 of the gate 291 clears the surface of the chute plate 319. The amount of clearance may be a desired amount larger than the size of the particles treated so that when the gate 291 is against the stop pins 299 a very thin film of particles may pass, but in any event, for any position of'the gate 291, one of the functions of the automatic valve means of which the gate 291 is a part is to bring the particles to rest before they are fed to the succeeding treating zone, as

' will more fully appear.

which as here shown is formed in the headof the bolt and extends into a part of the shank thereof. The recesses 399 are adapted to cooperate respectively with knife edge portions 391 formed on the ends of headless screws 999. The screws 999 are in threaded engagement respectively with threaded holes in a pair of brackets 399 welded or otherwise suitably fastened to the wall 299 of the intermediate hopper 52a, the outer surfaces of the brackets 399 being respectively flushwith the end walls 299, 219 of the hopper. The screws 398 are held in desired position by jam nuts 9l9 bearing against the brackets 399. The ends of the gate are provided with right. angle recesses 9H for purposes of clearance of the supportlngparts.

As here shown the axes of the screw bolts 394 are in the plane defined by the upstream sinare accessible from the outside of the walls 9b,

It will be apparent that. with the weights 3 in any given like position on the rods 319 the effective 'moment arm on which the weights act to hold the gate 291 against the stops 299 will be a line normal to the line defined by the knife edge margins M2 to a vertical plane through the center of gravity of the weights. Sincethe distance of a vertical plane through the center of gravity of the weights 3" from the line definedby the knife edge margins 9I2 will increase upon opening or incipient opening of the gate 291, the effective moment arm also will increase. Obviously the amount of this increase for a given operative opening of the gate 291 may be adjusted by changing the position of the weights 9" on the rods 9, the amount of increase being less when the weights are higher on the rods than when they are lower.

Furthermore, the moment arm onwhich the weights 9i3 act when the gate 291 is against the stops 299 may be increased for any given position of the weights on the rods, by adlustingjthe rods so that they extend downwardly toward the left, as viewed in Figure 14, instead of vertically downwardly as shown in the drawings. 7 v

Hence, the amount of material banked up against the up-stream side of the gate 291 necessary to cause incipient opening of the g te may be selected by the proper adjustment.

By reason of the construction and arrangement of the valve means I" (b through h), the particles are not only brought to rest'before they are fed to each succeeding treating zone, but a uniform distribution of the particles over the width of the respective zone is automatically insured, as will more fully appear hereinafter in connection with the operation of the apparatus.

Referring now more particularly to Figures 20 also disposed. Inv the arrangement shown the flexible conduit 91 is connected to the pipe 939 which is adapted to discharge material onto the feed screw 11. atits center, whereby rotation of the feed screw 11 (counterclockwise as seen in Fig-. ure 20,'or Figure 3,for example), causes the.

material to be moved from the center of the feed hopper 93 in opposite directions toward the ends of the hopper 93. The pipes '3" through 399,.

herein iter further described, are here shown as closed y can. Ill. These piper. as well as the elevator ll, are not in use in the reed arrangement shown in Figures 20, 21.

Assuming now that material is being fed to the hopper II as shown in Figures 20 and 21, and assuming further that the valve bodies Ill, Ill of the valve means H are open equal amounts, material will fall through the apertures I08 and thence through the open valve means IID onto the negative electrode II2a down which the material will slide as a stream of particles, the stream being comparable to a film or sheet of a thickness depending upon the amount of opening of the valve means III), the sheet being of uniform thickness and extending over substantially the entire width of the electrode I I2a.

The positive electrodes will be subjected to a desired high potential and will be so spaced by adjustment with respect to the respective negative electrodes, that, for a given material to be treated, the susceptible or more susceptible component particles will be influenced to the desired extent.

In the free space directly between the positive electrode I 23a and the negative electrode In, the lines of force of the electrostatic field are parallel to each other and normal to the respective electrodes, and the electrostatic field as a. whole extends downwardly at an angle to the horizontal, even if the plane of the positiveelectrode Illa, within the limits of desired operative adjustment, is not parallel to the plane of the negative electrode II2a. The latter may be the case if for any reason it is desired that the intensity of the electrostatic'field be less in its upper 'portion than in its lower portion, or vice versa.

As the stream of particles slides under the insulating baflle Illa, susceptible particles that might rise in the fringe field extending from the upper margin of the positive electrode I23a, are kept by that bailie from getting on top of the electrode Illa, and such particles fall back on the negative electrode and eventually continue with the stream thereon. When the stream on the negative electrode Illa gets into the free field between the positive and negative electrodes, susceptible particles rise into the electrostatic field and since this field extends downwardly at an angle to the horizontal and the force of gravity is at the same time acting on the particles and also influences their direction of movement in suspension in the field, as soon as any particle leaves the negative electrode, these susceptible particles do not rise in a direction upwardly at right angles to the negative electrode but tend to move toward a lower portion of the field considered as a whole. Some of the particles may reach the positive electrode, be charged positively, and fall back on the negative electrode at a. lower level; others may make a downward flight in the field without reaching the positive electrode, and again land on the negative electrode from which they may again make a downward flight in suspension in the field eventually passing over the top of the dividing plate Illa into the tails hopper 50a; and others may go into suspension in the field and make a single downward flight in the field, over the dividing plate Illa and into the tails hopper 50a. A large number of susceptible particles may be making flights in the field at one time, so that this mass of particles may be likened to a downwardly rolling cloud of particles. Those particles which are in flight at and above the dividing plate between the lower margin of the electrode I23a aseaias' beyond the discharge edge Illa. The remaining,

particles, which are the heads as far as'the zone A is concerned, fall off of the margin Illa of the negative electrode, or hit the upstream face of the dividing plate Illa, and these particles of course enter the intermediate hopper 52a.

Any susceptible particles which have passed over the dividing plate Illa and which might undesirably rise in the fringe electrostatic field and the wall I28a of the tails hopper, strike the bafile 2l6 and .fall back into the tails hopper out of range of the field.

The particles which enter the intermediate hopper 52a are discharged through the apertures 268 and come to rest against the gate 291 of the automatic valve means M51), or against particles banked at the clearance space between the lower margin of the gate and the chute plate 218. A very thin uniform film of particles may pass from the bank of particles through the clearance space even. when the gate 291 is against the stop pins 298. When a sufllcient amount of particles is banked up against the gate 291, the gate opens a certain amount. Meanwhile particles arev being continuously discharged from the intermediate hopper 52a, replenishing the bank of particles against the gate 291, so that for a given discharge rate from the hopper 52a a balance will be reached when the gate 291 is open a certain amount, particles being continuously discharged through the gate onto the chute plate 218 and thence onto the negative electrode I I 2b of the zone B in a sheet of uniform thickness.

The rate of discharge from the intermediate hopper 52a depends of course upon the rate at which particles enter the hopper from the zone A and this in turn depends, for one thing, upon the initial flow rate permitted by the feed valve means IIIl. A change in the adjustment of the feed valve means IIO resulting in a different fiow rate into and from the intermediate hopper 52a will result in automatic adjustment of the gate 291 to a new position. Furthermore, fora given adjustment of the feed valve means III), the rate of fiow into and from the intermediate hopper 52a depends upon the amount of susceptible particles extracted from the sheet of particles flowing down the electrode I I2a of the zone A. Since susceptible particles are extracted from the sheet of particles flowing down the electrode I I2a it will be evident that the rate of discharge from the intermediate hopper 52a will be lessthan the rate of discharge through the feed valve means IIII, but the valve means Il5b automatically adjusts for this difference so that while the volume or flow rate from the valve means Il5b will be less than from the feed valve'means I II), the particles are distributed over the width of the zone B in a sheet of uniform thickness though of less thickness than in the zone A. Thus; if for any reason, the rate of discharge from the intermediate hopper 52a changes, the valve means Il5b automatically adjusts for the change.

The actions hereinbefore described in connection with the zone A also take place in all of the subsequent zones B through H. In each zone susceptible particles are separated from the streams of particles on the respective negative electrodes, 

